Open AccessInfluence of cyanobacteria, mixotrophic flagellates, and virioplankton size fraction on transcription of microcystin synthesis genes in the toxic cyanobacterium Microcystis aeruginosa
Author(s) -
Scherer Pia I.,
Absmeier Carolin,
Urban Maria,
Raeder Uta,
Geist Juergen,
Zwirglmaier Katrin
Publication year - 2018
Publication title -
microbiologyopen
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.881
H-Index - 36
ISSN - 2045-8827
DOI - 10.1002/mbo3.538
Subject(s) - cyanobacteria , microcystin , microcystis aeruginosa , mixotroph , microcystis , biology , microbiology and biotechnology , synechococcus , bacteria , botany , heterotroph , genetics
Abstract Toxic cyanobacteria such as Microcystis aeruginosa are a worldwide concern in freshwater reservoirs. Problems associated with their mass occurrence are predicted to increase in the future due to global warming. The hepatotoxic secondary metabolite microcystin is of particular concern in this context. This study aimed to determine whether co‐occurring microorganisms influence the expression of microcystin biosynthesis genes. To this end, we performed cocultivation experiments and measured mcyB and mcyD transcripts in M. aeruginosa using RT ‐ qPCR . We utilized representatives from three different plankton groups: the picocyanobacterium Synechococcus elongatus , the unicellular flagellate grazer Ochromonas danica , and virioplankton from two different lakes. The presence of S. elongatus significantly increased mcyB and mcyD transcription in M. aeruginosa . Cocultivation with the mixotrophic chrysophyte O. danica did not increase the transcription of mcyB and mcyD ; in fact, mcyD transcripts decreased significantly. The virioplankton size fraction of environmental water samples induced a significant increase in mcyB and mcyD transcription when obtained from lakes with cyanobacterial blooms. Our results show that co‐occurring microorganisms influence the expression of microcystin biosynthesis genes in M. aeruginosa .